the egg is good advice because it has the protein needed. is the chicken walking in circles or just standing around? Also give them some apple juice in place of the water for a few hours. They love it and it will give them some energy.
whenever I have a chicken or a baby that seem low on energy or is listless I give them some apple juice and also crush up some grapes and tomatoes for them to eat. That always gives them a pick me up.
Thanks for the comments. I got into the habit of feeding my chickens popcorn because they really love it and even look forward to it. When i walk to the coop they are ready for it. I asked because I began to see the egg shell easily cracking and wondered if the popcorn was substituting important...